If you've watched David Fincher's Netflix original series Mindhunter, chances are you've done your fair share of Googling the real stories behind the serial killers featured on the show. While infamous men like the "Co-Ed Killer" Ed Kemper and the "Shoe Fetish Slayer" Jerry Brudos played major roles during season one, the story of perhaps the most widely known among them — notorious "BTK Strangler" Dennis Rader — was just being introduced as viewers were left awaiting season two before they could learn more.

He currently remains locked behind bars at El Dorado Correctional Facility in Kansas, serving ten consecutive life sentences (175 years) for those crime, but that doesn't mean anyone will soon forget his terrible legacy.

Here are 11 chilling facts about the real life BTK Strangler, Dennis Rader.

1. He spent the majority of his life in Kansas.

Born Dennis Lyn Rader on March 9, 1945 in Pittsburgh, Kansas, he grew up in Witchita, the eldest of four sons belonging to Dorothea Mae Rader (née Cook) and William Elvin Rader.

"By his own account and several reports, he engaged in animal torture during his early years, hanging cats and dogs in barns, and harbored a sexual fetish for women's underwear. After attending the Kansas Wesleyan University between 1965 and 1966, he was in the U.S. Air Force until 1970, stationed in Texas, Alabama, Okinawa, South Korea, Greece, and Turkey. During this time, he would peep at women undressing and burglarize houses to steal womens' underwear."

2. From the outside, he appeared to be a model citizen.

Once he left the Air Force, Rader married a woman named Paula Dietz on May 22, 1971, with whom he had two children, son Brian and daughter Kerri. After completing an associate's degree in Electronics and a bachelor's degree in Administration of Justice, he went to work as an assembler for an outdoor supply company.

He then went on to install private home security systems for ADT Security Services from 1974 to 1988. In many cases the homeowners were choosing to purchase such protection due to their fear over the BTK killings.

He briefly worked as a census field operations supervisor for the Wichita area, and then as a dogcatcher and compliance officer in Park City. While in this role, "neighbors recalled him as being sometimes overzealous and extremely strict. One neighbor complained he euthanized her dog for no reason."

Not only was Rader an member of Christ Lutheran Church, but he was elected president of the church council and served as a Cub Scout leader.

Rader nervously entered the home expecting to find Julie, 33, and possibly her two young children, Joe Jr., 9, and Josephine, 11. Unexpectedly, he also found Joseph Otero, 38, also at home, along with the family dog. He suffocated all four members of the family in the master bedroom before taking Josephine to the basement where he hung her and ejaculated on her bound, dead body. Their bodies were found later that same day by the Oteros' 15-year-old son, Charlie.

Eventually, the DNA samples he left at the scene of this crime and others would be use in court. And while the murders of the Otero family did not go as smoothly as he had planned, they did establish his pattern of behavior: Binding, torturing, and killing.

4. His desperate need for attention is particularly noteworthy.

"In October 1974, Rader placed a letter in a public library book in which he took responsibility for killing the Oteros. The letter ended up with a local newspaper, and the poorly written note gave authorities some idea of who they were dealing with. Rader wrote, 'It's hard to control myself. You probably call me 'psychotic with sexual perversion hang-up.' He warned that he would strike again, noting, 'The code words for me will be bind them, torture them, kill them, B.T.K.' The initials stuck, and the murderer came to be known by variations of the 'BTK killer' moniker, or simply 'BTK.'"

He also sent the police photographs of his bound victims, along with letters he referred to as chapters. He once even sent the police a word puzzle that contained last name hidden within the text.

Over the course of the three decades he remained at-large, his list of aliases included these:

BTK

​Ethan Truman

Happ Kakemann

​Bill Thomas Killman

​The BTK Strangler

The BTK Killer

The Wichita Strangler (self-named)

The Poetic Strangler (self-named)

The Asphyxiater (self-named)

The Garrote Phantom (self-named)

The Bondage Strangler (self-named)

The Wichita Hangman (self-named)

5. He had a portable "hit kit."

"Each time he struck, Rader said he was armed with what he calls his hit kit... 'Plastic bags, rope, tape, knife, gun... all those would be in the kit and I'd have then in the house and gather them up."

6. He blamed his crimes on something called "Factor X."

Dennis was a self-proclaimed "serial killer fan" and he claimed that Jack The Ripper to Ted Bundy to the Son of Sam had the same Factor X as he did.

“I knew somewhere along the line of eighth grade or freshman in high school that I had some abnormal tendencies at that point in time. But it exploded on January 15, 1974. That’s when the ball game exploded. You know, at some point in time, someone should have picked something up from me and identified it.”

7. He received sexual gratification from terrorizing his victims.

The process of hunting and stalking his potential victims was a huge part of what made these crimes so exciting for Rader. He would dedicate significant time to learning the movements and routines of the women he targeted. If something seemed off or something seemed like it would make the murder too challenging to carry out, he would simply move on to his next potential victim. After his arrest in 2005, many women came forward with stories about nights on which they believe he may have intended to kill them, but luck took them out of their routine, and therefore out of his planned attack.

Part of the reason he enjoyed staying in contact with the press was the thrill he got from the sense of terror he knew he was inflicting on the people around him in Wichita. He titled his attack on 25-year-old Nancy Jo Fox "Project Fix Hunt."

"That was part of his MO: He told a few of his victims that he had a sexual problem and he needed to do some bondage sex with them. He became aroused when he revealed his ruse. Fox asked if she could use the bathroom before they just 'get it over with.' Once she came out of the bathroom he handcuffed her, threw her on the bed, and strangled her. As she recovered after a pause, Rader later said that he whispered in her ear, telling her, 'I was BTK, I was a bad guy.’ And then she really squirmed and then — I pulled — put the pressure down on it.' The excitement of her knowing his infamous identity was the thrill Rader seeked; after she died he masturbated on her."

8. There was (at least) one who got away.

After what he believed was the perfect murder of Fox, he set his sights on a young widow named Anna Williams. He followed his usual pattern of stalking her and getting to know her routine, and one night in April of 1978, when he expected her to be home, he broke into her house, cut the phone lines, and waited for her to return from square dancing class as was her habit. Luckily for Anna, her life was saved when she decided visit her daughter after the class instead. Rader waited for her until 10 pm before finally leaving.

When Anna did return home, she found the phone lines had been cut, rushed to her neighbor's and called the police, who found a noose made from wire next to her bed. She never spent another night in the home, but a few months later her daughter went to collect her mail and found a letter addressed to her deceased husband, "c/o Anna." Inside the envelope was pair of her pantyhose, a drawing of what he had intended to do, and a poem, which included the line, “Oh Anna Why Didn’t You Appear?”

9. His huge ego eventually did him in.

Although Rader thought quite highly of himself, he was not as intelligent as he believed himself to be. His first letter to the press was so riddled with errors that the police initially believed that he must have written it that way on purpose to throw them.

“I write this letter to you for the sake of the tax payer as well as your time. Those three dude you have in custody are just talking to get publicity for the Otero murders. They know nothing at all. I did it by myself and with no ones help. There has been no talk either. Let’s put this straight.”

Once when his own wife came across a letter he was writing to someone she remarked, "You spell just like BTK," but she never made the actual connection.

After he killed Dolores Davis in 1991, Rader went on a murder hiatus of sorts, and his case grew cold. But when the Witchita Eagle reported that BTK must either be in jail or dead due to the lack of "activity," Rader, desperate to regain attention, sent the newspaper a letter claiming responsibility for an unsolved murder in 1986. This was the start of chain of coded messages exchanged over the course of the next year with police and press.

At one point Rader included the following note along with a packet of documents detailing plans for future murders.

"Can I communicate with Floppy and not be traced to a computer. Be honest. Under Miscellaneous Section, 494, (Rex, it will be OK), run it for a few days in case I'm out of town-etc. I will try a floppy for a test run some time in the near future-February or March."

This was Rader's coded way of asking the police to run an ad in the newspaper stating, "Rex, it will be OK," if he would be able to send them a floppy disk without it being traced back to him. They did as he asked and two weeks later he sent them a disk they led them to Rader via a computer at his church.

“'I need to ask you, how come you lied to me? How come you lied to me?' Rader asked [Witchita Kansas police Lt. Ken] Landwehr near the start of what would become a 32 hour inter­rogation-turned-confession.

'Because I was trying to catch you,' Landwehr replied matter of factly.

'He couldn’t get over the fact that I would lie to him,' Landwehr [said later]. “He could not believe that I did not want this to go on forever.'

Rader referred to the floppy disk again later in the interrogation, saying he knew he was taking a 'big gamble' by sending it to the TV station. 'I really thought Ken was honest when he gave me — when he gave me the signal it can’t be traced,' he said. 'The floppy did me in.'"

10. His daughter sent her own letter to the press.

Rader's family knew absolutely nothing about his hideous double life until they learned of it along with the rest of the public. His wife was granted an emergency divorce after his arrest, and has remained understandably silent.

My family is done, we are tired. We are not news, we are not a story to be exploited & profited on, to be twisted & retold to your liking whenever you want. Leave us, the families & the community out of it.

My dad is not a monster, that’s elevating him. He’s just a man, who choose to do some of the most horrible things a person can do. Not a monster, a man. A man who took 10 precious lives & tried to destroy countless others. He’s not worth the attention.

My mom is the strongest & bravest woman I know. She doesn’t need her life re-spun in a story or on the big screen. Her life is a true testament of all that is good & right in this world.

My family has tried hard to fight the good fight, to stand on our faith & live out a peaceful life. So let us live that life & please, leave us out of it. Out of the noise & chaos & the ugly & the awful.

She calls the book a "guided autobiography," in which he details the part of his personality he referred to as "'The Minotaur,' his personification of the sexual impulses and violent tendencies that made a serial killer."